The present invention relates generally to medical devices and more particularly to a biopsy member.
It is often necessary to obtain tissue samples for medical analysis and diagnosis. Physicians in many specialties commonly obtain biopsy samples in order to detect abnormalities, such as cancer.
Although there are numerous biopsy systems available, many biopsy systems use a member to cut a sample from inside a patient's body. Typically, the member may be a needle with a hollow longitudinal lumen and a sharp edge for cutting tissue. In order to retrieve the biopsy sample, the needle is inserted through the patient's skin, and the sharp edge cuts a tissue sample from inside the patient's body. The tissue sample is then collected inside of the longitudinal lumen of the needle. Alternatively, the biopsy member could be a brush or other collection instrument.
Various types of needles, cannulas, and other tissue collection structures may also be used in conjunction with a biopsy member. For example, a needle with a pointed tip may be inserted through the member, and may be used to guide the biopsy member to the desired target tissue. The member may also be inserted through a guide cannula or cutting cannula. The cannula may provide a pathway through non-targeted tissue to minimize damage to the non-targeted tissue. If the cannula has a sharp distal edge for cutting, the cannula may also be used to cut the tissue sample from the target tissue.
After the biopsy sample has been cut from the target tissue, the biopsy member may be withdrawn from the patient, and the biopsy sample may be retrieved from the distal end of the member. Alternatively, the biopsy sample may be retrieved from the longitudinal lumen of a biopsy needle while the needle remains in the patient's body by drawing the biopsy sample proximally through the lumen and out an exterior port of the biopsy needle.
One type of biopsy member that is used to collect biopsy samples has a helical screw blade at the distal end of a cannula. This type of biopsy member is typically driven into the target tissue by rotating the member so that the helical blade screws into the target tissue like a corkscrew. The tissue sample may then be separated from the target tissue by advancing a cutting cannula over the helical screw blade, or by withdrawing the member which causes the helical blade to longitudinally cut through portions of the sample that extend through the helical gap of the blade.
Biopsy members with helical screw blades are typically driven into the tissue by manually rotating the member. However, this has some disadvantages in practice. In particular, the length of time that a medical procedure takes increases the cost of the procedure and also can increase the anxiety of a patient. However, compared to some spring-loaded biopsy systems, manually driven helical screw members can be slower to use. Manually rotating a helical screw member can also be tedious for a physician, especially for a physician who performs numerous biopsies in hard tissue or bone. In addition, patients may be more psychologically affected by a manual biopsy system, when the patient is able to view the physician repeatedly moving his hand and/or wrist as the member is driven into their body. By comparison, a patient may be psychologically more comfortable with a biopsy system where the physician's body movements are minimized during the driving step of the procedure.
Accordingly, the inventor believes that an improved drive system for a biopsy member would be desirable for collecting biopsy samples.